Getting rid of a tangled web of phone chargers

Every night, [Roberto]’s kitchen counter is cluttered with three cell phones, three different cell phone chargers and a mess of wires until morning comes and the chargers are moved to a drawer for the following night. For [Roberto] this is a bit of a pain – a much easier solution would be to have a few USB ports embedded right into his kitchen backsplash. With the right tools, this can be easily done, resulting in a very professional looking installation for charging a trio of phones.

After removing a Euro AC outlet and replacing it with three iPhone chargers, [Roberto] simply soldered the six mains connections on the chargers to his house’s wiring. This resulted in a perfectly functional but rather ugly home project, though.

The next step was to machine a blank AC outlet cover for the three USB ports. [Roberto]’s CNC mill made quick work of this piece of plastic and turned it into a professional-looking installation.

Well no, they are obviously switch mode supplies, so they don’t have “tranformers running full time”. The standby power is probably very low. There could be a problem though, since they are not designed to be packed together that way. They could overheat when they are all on at once. That should be checked.

Well, this dude says he’s using iPhone chargers, and iPhones require some stupid handshake over the D+ and D- lines before it will charge the phone. For anything else you’d be correct.

Also, what kind of current are those rated for? I personally have had problems with my sister using my phone charger instead of the one meant for her phone (mine is rated for 0.8 amps, her’s is rated for 1.2 amps), which ended up killing my charger. Now I always check current ratings before I plug into anything, although I assume a rating of 1 amp would be safe for most devices.

Not to hand, but it’s easy to find. You just connect a couple of resistors to the D+ and D- lines, then use the power lines as usual. This is a simple, cheap, protocol that’s detected by the cleverer electronics in a phone or MP3 player. It lets your phone / MP3 know that the charger can supply more than the USB standard 500mA, without needing any complex systems in the charger. Have a look.

the ‘stupid’ handshaking you refer to is actually standard spec… any device drawing substantial current without checking the USB socket can supply it is out of spec, and could potentially damage equipment which didn’t expect to have 10W drawn from it to charge a tablet.

Almost every kitchen you go (in the US) you will find “15A” devices on the 20A circuits… It’s pretty much standard practice. 20A outlets have the side-ways flat prong, like a side-ways “T”…

The only time a 15A device on a 20A circuit is not acceptable, from my understanding, is when you have just a single device (outlet) on the entire 20A circuit. It goes without saying that the conductors in the wiring must be appropriate for 20A of course, but the devices themselves are OK at 15A.

One other thing to note–the linked outlet/USB is not a “GFCI” type outlet. All kitchen outlets need to be GFCI protected, so you’d want to make sure that if you bought this it was downstream (fed by) a GFCI outlet (or breaker)–In my kitchen I have outlets every 2′, so every other outlet is a GFCI and the ones that aren’t are fed by one.

Of course ugly is relative ;) I bring up the National Electric Code because I live in the USA. Probably not NEC friendly, unless the chargers ha a volume > = to the volume the receptacle takes up in the box, a heat dissipation thing I have been told. As long as fire occurs for any reason it will never be a problem. Anyway the NEC is fairly low voltage low current friendly. Making a simple matter to retro fit a home with USB jacks throughout a home feed from a single power source, doing what you have to do at the jacks to make iProducts happy. The only problem I’d see is a voltage drop though wire that’s easily ran & hidden.

A few clarifications. They are genuine Apple chargers, adequately fused and protected. Each draws 0.3W from the mains (do your math). Temperature inside the outlet goes just to 38C with thee chargers at full power, charging three devices from empty battery at the same time, with 24C at home. This is no more risky than having three chargers in three outlets. If anything, having them inside the wall (concrete, bricks) is actually safer. Appart from that, there is nothing flammable around.